fix plenty of lint warnings, make some for loops into foreach, remove unused imports and throw exceptions

OpenPGP-Keychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpHelper.java

@@ -193,11 +193,10 @@ public class PgpHelper {
      * @param context
      * @param progress
      * @param file
-     * @throws FileNotFoundException
      * @throws IOException
      */
     public static void deleteFileSecurely(Context context, ProgressDialogUpdater progress, File file)
-            throws FileNotFoundException, IOException {
+            throws IOException {
         long length = file.length();
         SecureRandom random = new SecureRandom();
         RandomAccessFile raf = new RandomAccessFile(file, "rws");

OpenPGP-Keychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpImportExport.java

@@ -79,8 +79,9 @@ public class PgpImportExport {
 
     public boolean uploadKeyRingToServer(HkpKeyServer server, PGPPublicKeyRing keyring) {
         ByteArrayOutputStream bos = new ByteArrayOutputStream();
-        ArmoredOutputStream aos = new ArmoredOutputStream(bos);
+        ArmoredOutputStream aos = null;
         try {
+            aos = new ArmoredOutputStream(bos);
             aos.write(keyring.getEncoded());
             aos.close();
 
@@ -95,7 +96,8 @@ public class PgpImportExport {
             return false;
         } finally {
             try {
-                bos.close();
+                if (aos != null) aos.close();
+                if (bos != null) bos.close();
             } catch (IOException e) {
             }
         }
@@ -156,7 +158,7 @@ public class PgpImportExport {
     }
 
     public Bundle exportKeyRings(ArrayList<Long> keyRingRowIds, int keyType,
-                                 OutputStream outStream) throws PgpGeneralException, FileNotFoundException,
+                                 OutputStream outStream) throws PgpGeneralException,
             PGPException, IOException {
         Bundle returnData = new Bundle();
 

OpenPGP-Keychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpKeyOperation.java

@@ -190,7 +190,7 @@ public class PgpKeyOperation {
     }
 
     public void changeSecretKeyPassphrase(PGPSecretKeyRing keyRing, String oldPassPhrase,
-            String newPassPhrase) throws IOException, PGPException, PGPException,
+            String newPassPhrase) throws IOException, PGPException,
             NoSuchProviderException {
 
         updateProgress(R.string.progress_building_key, 0, 100);